Hmm. I might have guessed the other way around, with /ai/ as more BE and /i/ as more AE. The traditional British pronunciation of Latin used English 'long' vowels (ate, eat, I'd, owed, rude). So for example legal terms tend to keep that quaint 'old' pronunciation: 'nisi' /naisai/.
Or there might also be a difference depending on the following sound: a consonant vs. a vowel (or semivowel)?
But in practice, I'm not sure my own pronunciations follow any theory. So maybe the best I can do is list examples.
I started out with a category called
chiefly /ai/ ,
but on reflection I moved all of those to the next category, namely, 'either.' Sorry not to be more decisive -- though it could still be true that when there's a choice, AE is more likely to go for /ai/.
only /i/ or /ɪ/
(2) foci, loci
I would vote firmly for /'fo sai/ and /'lo sai/. I don't actually think there's any room for discussion here.
One that may be different in AE and BE, though, is 'fungi,' which we in AE call /'fʌn dʒai/.